State-oriented Noninterference for CCS

We address the question of typing noninterference (NI) in the calculus CCS, in such a way that Milner's translation into CCS of a standard parallel imperative language preserves both an existing NI property and the associated type system. Recently, Focardi, Rossi and Sabelfeld have shown that a variant of Milner's translation, restricted to the sequential fragment of the language, maps a time-sensitive NI property to that of Persistent Bisimulation-based Non Deducibility on Compositions (PBNDC) on CCS. However, since CCS was not equipped with a type system, the question of whether the translation preserves types could not be addressed. We extend Focardi, Rossi and Sabelfeld's result by showing that a slightly simpler variant of Milner's translation preserves a time-insensitive NI property on the full parallel language, by mapping it again to PBNDC. As a by-product, we formalise a folklore result, namely that Milner's translation preserves a behavioural equivalence on programs. We present a simple type system ensuring PBNDC on CCS, inspired by existing type systems for the π-calculus. Unfortunately, this type system as it stands is too restrictive to grant the expected type preservation result. We sketch a solution to overcome this problem.     

Histone Deacetylase Inhibitors Ameliorate Morphological Defects and Hypoexcitability of iPSC-Neurons from Rubinstein-Taybi Patients

Rubinstein-Taybi syndrome (RSTS) is a rare neurodevelopmental disorder caused by mutations in CREBBP or EP300 genes encoding CBP/p300 lysine acetyltransferases. We investigated the efficacy of the histone deacetylase inhibitor (HDACi) Trichostatin A (TSA) in ameliorating morphological abnormalities of iPSC-derived young neurons from P149 and P34 CREBBP-mutated patients and hypoexcitability of mature neurons from P149. Neural progenitors from both patients’ iPSC lines were cultured one week with TSA 20 nM and, only P149, for 6 weeks with TSA 0.2 nM, in parallel to neural progenitors from controls. Immunofluorescence of MAP2/TUJ1 positive cells using the Skeletonize Image J plugin evidenced that TSA partially rescued reduced nuclear area, and decreased branch length and abnormal end points number of both 45 days patients’ neurons, but did not influence the diminished percentage of their neurons with respect to controls. Patch clamp recordings of TSA-treated post-mitotic P149 neurons showed complete/partial rescue of sodium/potassium currents and significant enhancement of neuron excitability compared to untreated replicas. Correction of abnormalities of P149 young neurons was also affected by valproic acid 1 mM for 72 h, with some variation, with respect to TSA, on the morphological parameter. These findings hold promise for development of an epigenetic therapy to attenuate RSTS patients cognitive impairment.     

CFRP laminates under low‐velocity impact conditions: Influence of matrix and temperature

In this work, carbon fiber‐reinforced composites (CFRP), respectively, based on a vynilester and epoxy resin were loaded under low‐velocity impact condition to highlight the influences of different matrices and temperature on their dynamic response. In particular, measurements were performed at room and the low temperature of ?25°C on samples simply supported by air to exactly simulate the incidental impact during the structure service and having the same thickness. Impact tests were carried out at penetration to obtain the complete load–displacement curve and to measure the penetration energy, and at different energy levels, 5, 10, and 20 J, to investigate the influence of the matrix on the damage start and propagation. After the impact tests, the specimens were nondestructively investigated by the ultrasound technique to measure the delamination. The interesting results obtained on carbon fiber laminates impacted at room and lower temperature are here reported and compared. In general, better behavior was noted for vinyl ester‐based composites, extensively used in the naval field, thanks to their low absorption for humidity. POLYM. ENG. SCI., 59:2429–2437, 2019. © 2019 Society of Plastics Engineers     

Si-substituted hydroxyapatite nanopowders: Synthesis, thermal stability and sinterability

Synthetic hydroxyapatites incorporating small amounts of Si have shown improved biological performances in terms of enhanced bone apposition, bone in-growth and cell-mediated degradation.This paper reports a systematic investigation on Si-substituted hydroxyapatite (Si 1.40 wt%) nanopowders produced following two different conventional wet methodologies: (a) precipitation of Ca(NO₃)₂·4H₂O and (b) titration of Ca(OH)₂. The influence of the synthesis process on composition, thermal behaviour and sinterability of the resulting nanopowders is studied.Samples were characterised by electron microscopy, induced coupled plasma atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N₂ adsorption measurements, X-ray diffraction and dilatometry. Semicrystalline Si-substituted hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 84 and 110 m²/g. Pure and Si-substituted hydroxyapatite nanopowders derived from Ca(NO₃)₂·4H₂O decomposed around 1000 °C. Si-substituted hydroxyapatite nanopowders obtained from Ca(OH)₂ were thermally stable up to 1200 °C and showed a distinct decreased thermal stability with respect to the homologous pure sample. Si-substituted hydroxyapatites exhibited higher sintering temperature and increased total shrinkage with respect to pure powders. Nanostructured dense ceramics were obtained by sintering at 1100 °C Si-substituted hydroxyapatites derived from Ca(OH)₂.     

Natural fluctuations of mercury and lead in Greenland lake sediments

Given the current scenario of increasing global temperatures, it is valuable to assess the potential influence of changing climate on pollution distribution and deposition. In this study we use long-term sediment records from three lakes (spanning ca. 1000, 4800, and 8000 years, respectively) from the Greenland west coast to assess recent and long-term variations in mercury (Hg) and lead (Pb), including stable Pb isotopes (206Pb and 207Pb), in terms of pollution and climate influences. The temporal trends in sediment deposited from about the mid-19th century and forward are in general agreement with the history of industrial emissions at lower latitudes. Therefore, in recent sediment a possible influence from changing climate is difficult to assess. However, by using deeper sediment layers we show that changes in Greenland climate caused changes in the lake influx of material from regional aeolian activity, which resulted in large fluctuations in Hg and Pb concentrations and 206Pb/207Pb ratios. The aeolian material is primarily derived from glacio-fluvial material with low Hg and Pb concentrations and a different isotopic composition. For one of the lakes, the fluctuations in Hg concentrations (10 to 70 ng g(-1)) prior to the 19th century are equal to the anthropogenic increase in the uppermost layers, suggesting that when studying recent concentrations and time trends of pollution in relatively low-contaminated areas such as the Arctic, the early natural fluctuations must be considered.     

Experimental characterization of Ti6Al4V T joints welded through linear friction welding technique: microstructure and NDE

Linear friction welding (LFW) is an innovative solid-state welding technique that allows to manufacture joints with high mechanical properties. This technology has various applications in the aerospace field; in particular it is used to weld massive structural components made of Ti6Al4V. This paper deals with the experimental study of Ti6Al4V T-joints welded through LFW, with particular focus on the effectiveness of ultrasonic control in detecting and distinguishing welding defects within the joints. Aiming to this scope, joints with different properties were manufactured and tested:some were free from defects but with different metallurgy, and some had different types of defects. The results obtained proved that the ultrasonic control was an effective method to detect and identify defects in linear friction welded titanium joints, moreover it was possible to get information regarding the microstructure and in particular the extension of the different metallurgical zones induced by the welding process.     

Characterization of Active Dry Wine Yeast During Starter Culture (Pied de Cuve) Preparation for Sparkling Wine Production

The preparation of yeast starter culture (Pied de Cuve) for producing sparkling wine with the traditional method is a key factor for manufacturing a good Prise de mousse. In this paper, the evolution of total yeast population, its viability during Pied de Cuve preparation, and the pressure profile during the 2nd fermentation in 2 different base wines made from Bombino bianco and Chardonnay grapes were investigated using 4 different commercial active dried yeasts. The study proves that despite the initial differences observed throughout the acclimatization phase, all the tested strains showed similar results on either the total population (from 8.2 × 10⁷ cells/mL to 1.3 × 10⁸ cells/mL) or cellular viability (from 70% to 84%). Independently from the base wine tested, the kinetic of sugar consumption was faster during the gradual acclimatization to the alcoholic medium (phase II) and slower during the preparation of starter culture in active growth phase (phase III). During both of these phases Saccharomyces cerevisiae bayanus Vitilevure DV10^® (Station ?notechnique de Champagne) proved to have a higher sugar consumption rate than the other strains. During the Prise de mousse, S. cerevisiae bayanus Lalvin EC‐1118^® (Lallemand) reached the maximum pressure increase within time in both base wines.     

Mixed Discontinuous Galerkin Approximation of the Maxwell Operator: Non-Stabilized Formulation

A non-stabilized mixed discontinuous Galerkin method for the discretization of the Maxwell operator on simplicial meshes is studied. In contrast to the stabilized scheme introduced in Houston, Perugia and Schötzau, Siam J. Numer. Anal., 42: 434–459, 2004, the proposed formulation contains no normal-jump stabilization; instead, it is based on discontinuous mixed-order elements for the approximation of the unknowns. A priori error bounds in the energy norm are derived that show convergence rates of the order in the mesh size h. The error analysis relies on suitable decompositions of discontinuous spaces and on stability properties of the underlying conforming spaces. The formulation is tested on a set of numerical examples in two space dimensions.This revised version was published online in July 2005 with corrected volume and issue numbers.